UMLS:C0243026 - FACTA Search

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Query: UMLS:C0243026 (sepsis)
52,417 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Human adrenomedullin (hAM), a potent vasodilatory peptide originally identified in pheochromocytoma, has been shown to be present in various human tissues and circulate in human plasma. We measured plasma concentrations of immunoreactive hAM in patients with sepsis who had been admitted to intensive care unit (ICU). Plasma hAM concentrations in 12 septic patients upon entering the ICU were extremely elevated (107 +/- 139 fmol/ml: mean +/- SD) compared to those of 16 age-matched normal subjects (7.9 +/- 3 fmol/mL). Among 10 patients with normal renal function, plasma hAM levels either decreased or increased during the hospital course; the former group survived and the latter group succumbed. Two patients with acute renal failure had markedly elevated plasma hAM levels during the early course, which declined rapidly during the recovery course. High performance liquid chromatography of plasma extracts from one patient with acute renal failure revealed a single major component of immunoreactive hAM coeluting with authentic hAM (1-52) during acute and recovery phase. Plasma hAM concentration showed positive correlations with heart rate, right atrial pressure, and serum creatinine concentration, but not with other hemodynamic variables. These data suggest that a marked increase in circulating hAM in sepsis may be caused by its decreased clearance and/or its enhanced synthesis by multiple organ dysfunction, and that increased endogenous hAM may be involved in the mechanism of cardiovascular abnormalities associated with sepsis.
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PMID:Increased circulating adrenomedullin, a novel vasodilatory peptide, in sepsis. 863 49

Posttranslational processing of the adrenomedullin gene product results in the formation of at least two biologically active peptides, adrenomedullin (AM) and proadrenomedullin N-20 terminal peptide (PAMP). Produced predominantly in the vasculature, both peptides are potent hypotensive agents, albeit via unique mechanisms of action. The gene is transcribed in a variety of other tissues including brain, pituitary, and kidney. Numerous actions have been reported most related to the physiologic control of fluid and electrolyte homeostasis. In the kidney, AM is diuretic and natriuretic, and both AM and PAMP inhibit aldosterone secretion by direct adrenal actions. In pituitary gland, both peptides at physiologically relevant doses inhibit basal ACTH secretion, again by apparently differing mechanisms. Additionally, AM antagonizes CRH-stimulated ACTH release. The peptides are produced in numerous brain sites, including hypothalamus and brainstem. Inhibition of AVP release has been reported and the physiologic significance of AM's ability to inhibit water drinking and salt appetite has been established. Thus the peptides appear to act in brain and pituitary gland to facilitate the loss of plasma volume, actions which complement their hypotensive effects in the blood vessel. Interestingly, direct cardiac effects (positive inotropism and chronotropism) and CNS actions (sympathostimulation) have been reported, leading to the hypothesis that these peptides also can exert important cardioprotective effects, helping to prevent vascular collapse during states of high AM secretion such as sepsis.
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PMID:Proadrenomedullin-derived peptides. 957 82

We demonstrate that adrenomedullin (AM) is produced and secreted from cultured murine monocyte/macrophage cell line (RAW 264.7) as well as mouse peritoneal macrophage. Immunoreactive (IR) AM secreted from RAW 264.7 cells was chromatographically identified to be native AM. To elucidate the regulation mechanism of AM production in macrophage, we examined the effects of various substances inducing differentiation or activation of monocyte/macrophage. Phorbol ester (TPA), retinoic acid (RA), lipopolysaccharide (LPS), and interferon-gamma (IFN-gamma) increased AM production 1.5-7-fold in RAW 264.7 cells in a dose- as well as time-dependent manner. By LPS stimulation, the AM mRNA level in RAW 264.7 cells was augmented up to 7-fold after 14 h incubation. RA exerted a synergistic effect when administered with TPA, LPS, or IFN-gamma, whereas IFN-gamma completely suppressed AM production in RAW 264.7 cells stimulated with LPS. Dexamethasone, hydrocortisone, estradiol, and transforming growth factor-beta dose-dependently suppressed AM production in RAW 264.7 cells. AM production was also investigated in mouse peritoneal macrophage. Primary mouse macrophage secreted IR-AM at a rate similar to that of RAW 264.7 cells, and its production was enhanced 9-fold by LPS stimulation. AM was found to increase basal secretion of tumor necrosis factor alpha (TNF-alpha) from RAW 264.7 cells, whereas AM suppressed the secretion of TNF-alpha and interleukin-6 from that stimulated with LPS. Thus, macrophage should be recognized as one of the major sources of AM circulating in the blood. Especially in cases of sepsis and inflammation, AM production in macrophage is augmented, and the secreted AM is deduced to function as a modulator of cytokine production.
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PMID:Production of adrenomedullin in macrophage cell line and peritoneal macrophage. 964 28

A large number of studies have been and are being carried out to examine the role of nitric oxide in the hyperdynamic and hypodynamic stages of sepsis. It remains unknown, however, whether adrenomedullin (ADM), a novel potent vasodilatory peptide, is up-regulated during hyperdynamic sepsis and, if so, whether its production is sustained during hypodynamic sepsis. To determine this, rats were subjected to sepsis by cecal ligation and puncture (CLP), followed by administration of 3 mL/100 g body weight normal saline to these and sham-operated animals. Blood samples were taken at 1, 1.5, 2, 5, and 10 h (2-10 h post-CLP represents the hyperdynamic stage of sepsis) or at 20 and 30 h after CLP (i.e., the hypodynamic stage). Plasma levels of ADM were measured by radioimmunoassay. Adrenomedullin gene expression in various tissues was examined at 2, 10, or 20 h after CLP by reverse transcription-polymerase chain reaction (RT-PCR). The results indicated that plasma levels of ADM did not increase at 1 and 1.5 h after CLP but increased significantly at 2 h after the onset of sepsis. Moreover, circulating ADM increased progressively at 5-20 h and remained elevated at 30 h after CLP. The increased levels of plasma ADM during sepsis were correlated with up-regulation of ADM mRNA in the small intestine, left ventricle, and thoracic aorta. In contrast, ADM gene expression in renal and hepatic tissues was not significantly altered following the onset of sepsis. The association between the up-regulated ADM and the occurrence of hyperdynamic circulation during the early stage of sepsis (both occur at 2 h after CLP) may indicate a possible cause and effect relationship between the two events. Since we have previously shown that ADM-induced vascular relaxation decreased at 20 h after CLP, it appears that the down-regulation of ADM receptors may be responsible for the transition from the hyperdynamic stage to the hypodynamic stage of sepsis.
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PMID:Up-regulation of a novel potent vasodilatory peptide adrenomedullin during polymicrobial sepsis. 984 Jun 56

Lipopolysaccharide (LPS), a potent inflammatory stimulus derived from the outer membrane of gram-negative bacteria, has been implicated in septic shock. Plasma levels of adrenomedullin (AM), a potent vasorelaxant, are increased in septic shock and possibly contribute to the characteristic hypotension. As macrophages play a central role in the host response to LPS, we studied AM production by LPS-stimulated macrophages. When peritoneal exudate macrophages from C3H/OuJ mice were treated with protein-free LPS (100 ng/ml) or the LPS mimetic paclitaxel (Taxol; 35 microM), an approximately 10-fold increase in steady-state AM mRNA levels was observed, which peaked between 2 and 4 h. A three- to fourfold maximum increase in the levels of immunoreactive AM protein was detected after 6 to 8 h of stimulation. While LPS-hyporesponsive C3H/HeJ macrophages failed to respond to protein-free LPS with an increase in steady-state AM mRNA levels, increased levels were observed after stimulation of these cells with a protein-rich (butanol-extracted) LPS preparation. In addition, increased AM mRNA was observed following treatment of either C3H/OuJ or C3H/HeJ macrophages with soluble Toxoplasma gondii tachyzoite antigen or the synthetic flavone analog 5, 6-dimethylxanthenone-4-acetic acid. Gamma interferon also stimulated C3H/OuJ macrophages to express increased AM mRNA levels yet was inhibitory in the presence of LPS or paclitaxel. In vivo, mice challenged intraperitoneally with 25 microg of LPS exhibited increased AM mRNA levels in the lungs, liver, and spleen; the greatest increase (>50-fold) was observed in the liver and lungs. Thus, AM is produced, by murine macrophages, and furthermore, LPS induces AM mRNA in vivo in a number of tissues. These data support a possible role for AM in the pathophysiology of sepsis and septic shock.
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PMID:Induction of adrenomedullin mRNA and protein by lipopolysaccharide and paclitaxel (Taxol) in murine macrophages. 974 63

Although circulating levels of adrenomedullin (ADM), a newly reported vasodilatory peptide with 52 amino acid residues in the human and 50 amino acid residues in the rat, are elevated during the early and late stages of sepsis, ADM levels in cardiovascular tissues and its precise localization remain to be determined. To study this, rats were subjected to sepsis by cecal ligation and puncture (CLP), followed by administration of 3 ml/100 g b.wt. normal saline to these and sham-operated animals. The heart and thoracic aorta were harvested at 5 h (i.e. the early stage of sepsis) and 20 h (late sepsis) after CLP. Tissue levels of ADM were determined by radioimmunoassay. The localization of ADM in the left ventricle and thoracic aorta was examined by using immunohistochemistry and electron microscopy techniques. The results indicated that ADM levels in the heart and thoracic aorta increased significantly at 5 h after CLP and remained elevated at 20 h after the onset of sepsis. Immunohistochemistry findings showed that ADM immunoreaction products were localized in the cytoplasm of the cardiac myocytes and aortic endothelial cells. Using electron microscopy, ADM immunoreaction products were found in the cytoplasmic matrixes. The immunostainings were also associated with the outer membranes of mitochondria and vesicles of the myocytes as well as vascular endothelial cells. It appears that the cardiovascular tissues, among other organ systems, contribute to the increased levels of plasma ADM under those conditions. Since ADM is localized in different cell populations in the heart and the large blood vessel (i.e. myocytes versus vascular endothelial cells), this peptide may play a differential role in regulating cardiac and vascular functions during sepsis as an autocrine and/or paracrine mediator.
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PMID:Adrenomedullin is upregulated in the heart and aorta during the early and late stages of sepsis. 1003 25

Two potent hypotensive peptides, adrenomedullin (AM) and proadrenomedullin N-terminal 20 peptide (PAMP), are encoded by the adrenomedullin gene. AM stimulates nitric oxide production by endothelial cells, whereas PAMP acts presynaptically to inhibit adrenergic nerves that innervate blood vessels. Complementary, but mechanistically unique, actions also occur in the anterior pituitary gland where both peptides inhibit adrenocorticotropin release. In the adrenal gland both AM and PAMP inhibit potassium and angiotensin II-stimulated aldosterone secretion. Natriuretic and diuretic actions of AM reflect unique actions of the peptide on renal blood flow and tubular function. In the brain AM inhibits water intake and, in a physiologically relevant manner, salt appetite. Both AM and PAMP act in the brain to elevate sympathetic tone, effects that mirror the positive inotropic action of AM in the heart. Cardioprotective actions in the brain and heart may be important counter-regulatory actions that buffer the extreme hypotensive actions of the peptides when released in sepsis. Thus the biologic actions of the proadrenomedullin-derived peptides seem well coordinated to contribute to the physiologic regulation of volume and electrolyte homeostasis.
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PMID:Adrenomedullin and the control of fluid and electrolyte homeostasis. 1009 93

Polymicrobial sepsis is characterized by an early, hyperdynamic phase followed by a late, hypodynamic phase. Although upregulation of adrenomedullin (ADM), a novel potent vasodilatory peptide, plays an important role in producing cardiovascular responses during the progression of sepsis, it remains unknown whether the clearance of this peptide is altered under such conditions. To determine this, male adult rats were subjected to sepsis by cecal ligation and puncture (CLP) followed by fluid resuscitation. At 5 h (i.e., the hyperdynamic phase of sepsis) or 20 h (the hypodynamic phase) after CLP, the animals were injected with 125I-labeled ADM through the jugular vein. Blood and tissue samples (including the lungs, kidneys, gastrointestinal tract, pancreas, spleen, mesentery, liver, brain, skeletal muscle, heart, and skin) were harvested 30 min after the injection and the radioactivity was determined. The results indicate that there were no significant alterations in tissue [125I]ADM distribution at 5 h after CLP compared to shams. At 20 h after CLP, however, there was a significant decrease in radioactivity in the lungs. In contrast, a significant increase of radioactivity was observed in all other organs except the liver and kidneys. The pulmonary distribution of [125I]ADM was found to be far greater than in any other organs tested, irrespective of the effect of sepsis. In separate groups of animals, injection of [125I]ADM into the left ventricle resulted in a significant decrease in radioactivity in the lungs of both sham and septic animals at 20 h after surgery. These results suggest that the lungs are the primary site of ADM clearance, which is significantly diminished during the late stage of sepsis. The decreased clearance of ADM by the lungs may play an important role in maintaining the sustained levels of plasma ADM under such conditions.
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PMID:Pulmonary clearance of adrenomedullin is reduced during the late stage of sepsis. 1021 48

Adrenomedullin (ADM) is a recently discovered peptide with potent vasorelaxing and natriuretic properties originally isolated from human pheochromocytoma. Adrenomedullin has been reported to be present in normal adrenal medulla, heart, lung and kidney as well as in plasma and urine. ADM shares some structural homology with calcitonin gene related peptide (CGRP). ADM acts on target cells through its unique receptors and CGRP1 receptors. In both cases cyclic AMP seems to be the main second messenger. ADM may function as a circulating hormone and as an autocrine/paracrine mediator involved in the regulation of cardiovascular system and renal function. Plasma concentration of ADM is elevated in patients with congestive heart failure, arterial hypertension, pulmonary hypertension, renal failure and sepsis suggesting its role in pathophysiology of these disorders. Recently another product od adrenomedullin gene, proadrenomedullin N-terminal 20-peptide (PAMP) has been described. This peptide has also vasodilating activity resulting from its inhibitory action on norepinephrine release from sympathetic endings and adrenal medulla.
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PMID:[Adrenomedullin]. 1035 50

We measured the plasma levels of adrenomedullin (AM), a novel vasodilating peptide, in 89 patients with various forms of systemic inflammatory response syndrome (SIRS) and 13 healthy volunteers serving as controls. Plasma levels of AM in SIRS (burns: 20.5 +/- 3. 2 fmol/ml [mean +/- SEM]; pancreatitis: 13.8 +/- 3.8 fmol/ml; trauma: 14.9 +/- 2.5 fmol/ml; traumatic shock: 41.1 +/- 7.8 fmol/ml; severe sepsis: 59.9 +/- 11.2 fmol/ml; septic shock: 193.5 +/- 30.1 fmol/ml) were significantly increased over those of controls (5.1 +/- 0.2 fmol/ml). The patients with traumatic shock or septic shock especially had higher levels of plasma AM than those with trauma or severe sepsis, respectively. These data showed that in patients with SIRS, plasma AM levels increased in proportion to the severity of illness. Subsequently, we measured the plasma levels of mediators such as tumor necrosis factor (TNF)-alpha, interleukin (IL)-6, IL-8, plasminogen activator inhibitor (PAI)-1, and thrombomodulin (TM) in patients with traumatic shock and septic shock. A significant correlation was observed between plasma AM and TNF-alpha levels in patients with septic shock, suggesting an important role for AM as well as of TNF-alpha in the pathophysiology of inflammation. Plasma AM and IL-8 levels correlated positively with Acute Physiology and Chronic Health Evaluation (APACHE) II score, peak multiple organ failure (MOF) score during the first month and prognosis in patients with septic shock, as did plasma IL-6 levels in patients with traumatic shock. The plasma AM level might serve as a useful marker for evaluating the severity of disease and as an early predictor of subsequent organ failure and outcome in septic shock.
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PMID:Increased plasma levels of adrenomedullin in patients with systemic inflammatory response syndrome. 1039 Mar 90

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